Conventionally, when devices are connected to each other in conformity with the High-Definition Multimedia Interface (HDMI) standard, a source device (such as an optical disc reproducing device) first receives extended display identification data (EDID) of a sink device (such as a television display device) to know the capability of the sink device, and then sends video and sound signals suitable for the sink device. The HDMI standard has been subjected to, for example, version upgrades to expand functions in accordance with improvements in computer technologies and requirement of the devices.
The HDMI standard is defined so as to be compatible between different versions. However, there can be devices that are not designed as specified by the HDMI standard, or cases in which improvement in performance makes it difficult to fully maintain interconnectivity between the devices.